:root{
  --bg:#fffaf3; --ink:#1d1b2e; --muted:#6b6880; --card:#fff; --line:#ece6da;
  --brand:#e8542a; --brand-d:#c63f1a; --accent:#2b2a6b; --ok:#1c8a5a;
  --r:14px; --shadow:0 6px 24px rgba(40,30,20,.08);
}
@media (prefers-color-scheme:dark){
  :root{--bg:#14131c; --ink:#f3f1ea; --muted:#a29fb5; --card:#1e1d2a; --line:#2f2d3f; --accent:#9d9bff; --shadow:0 6px 24px rgba(0,0,0,.4)}
}
*{box-sizing:border-box;margin:0}
html{scroll-behavior:smooth}
body{font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--ink)}
.wrap{max-width:1120px;margin:0 auto;padding:0 16px}
.sec{padding:56px 16px}
.narrow{max-width:760px}
h1,h2,h3{line-height:1.2}
h2{font-size:clamp(1.5rem,3vw,2rem);margin-bottom:24px}
a{color:inherit}

.nav{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--bg) 90%,transparent);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav-in{display:flex;align-items:center;gap:24px;height:62px}
.logo{font-weight:800;font-size:1.25rem;text-decoration:none}
.logo b{color:var(--brand)}
.links{margin-left:auto;display:flex;gap:20px}
.links a{text-decoration:none;color:var(--muted);font-weight:500}
.links a:hover{color:var(--brand)}
.cart-btn{border:1px solid var(--line);background:var(--card);color:var(--ink);padding:8px 14px;border-radius:999px;cursor:pointer;font-size:1rem}
.cart-btn span{background:var(--brand);color:#fff;border-radius:999px;padding:0 8px;font-size:.8rem;margin-left:4px}

.hero{background:linear-gradient(135deg,#fdeede 0%,#fff6ea 60%);}
@media (prefers-color-scheme:dark){.hero{background:linear-gradient(135deg,#221f33,#14131c)}}
.hero-in{display:grid;grid-template-columns:1.2fr 1fr;gap:32px;align-items:center;padding:64px 16px}
.eyebrow{color:var(--brand);font-weight:700;letter-spacing:.04em;font-size:.85rem;text-transform:uppercase}
.hero h1{font-size:clamp(2rem,5vw,3.2rem);margin:10px 0 14px}
.hero em{font-style:normal;color:var(--brand)}
.lead{color:var(--muted);max-width:520px}
.cta{display:flex;gap:12px;margin:24px 0}
.btn{display:inline-block;background:var(--brand);color:#fff;border:0;padding:12px 24px;border-radius:999px;font-weight:700;text-decoration:none;cursor:pointer;font-size:1rem;text-align:center}
.btn:hover{background:var(--brand-d)}
.btn.ghost{background:transparent;color:var(--ink);border:1.5px solid var(--line)}
.btn.ghost:hover{border-color:var(--brand);color:var(--brand)}
.btn.full{width:100%}
.stats{list-style:none;display:flex;gap:28px;padding:0}
.stats b{display:block;font-size:1.3rem}
.stats span{color:var(--muted);font-size:.85rem}
.hero-art{position:relative;height:300px}
.book{position:absolute;width:150px;height:220px;border-radius:6px 14px 14px 6px;box-shadow:var(--shadow)}
.b1{background:linear-gradient(160deg,#e8542a,#f2a05b);left:10%;top:30px;transform:rotate(-8deg)}
.b2{background:linear-gradient(160deg,#2b2a6b,#5a58c9);left:34%;top:0;transform:rotate(3deg);z-index:1}
.b3{background:linear-gradient(160deg,#1c8a5a,#6fd1a1);left:56%;top:44px;transform:rotate(11deg)}

.tools{display:flex;gap:12px;flex-wrap:wrap;justify-content:space-between;margin-bottom:24px}
.tabs{display:flex;gap:8px;flex-wrap:wrap}
.tabs button{border:1px solid var(--line);background:var(--card);color:var(--ink);padding:8px 16px;border-radius:999px;cursor:pointer;font-size:.95rem}
.tabs button.on{background:var(--ink);color:var(--bg);border-color:var(--ink)}
#search{border:1px solid var(--line);background:var(--card);color:var(--ink);padding:9px 16px;border-radius:999px;min-width:220px;font-size:.95rem}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:20px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);overflow:hidden;display:flex;flex-direction:column;transition:transform .2s,box-shadow .2s}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.cover{aspect-ratio:4/3;display:flex;align-items:flex-end;padding:16px;color:#fff;font-weight:800;font-size:1.15rem;line-height:1.25;position:relative;cursor:pointer;text-shadow:0 1px 6px rgba(0,0,0,.3)}
.badge{position:absolute;top:12px;left:12px;background:rgba(0,0,0,.35);padding:2px 10px;border-radius:999px;font-size:.72rem;font-weight:600;text-shadow:none}
.sale{position:absolute;top:12px;right:12px;background:#fff;color:var(--brand);padding:2px 10px;border-radius:999px;font-size:.75rem;font-weight:800;text-shadow:none}
.info{padding:14px 16px 16px;display:flex;flex-direction:column;gap:6px;flex:1}
.meta{color:var(--muted);font-size:.85rem}
.price{margin-top:auto;display:flex;align-items:baseline;gap:8px}
.price b{font-size:1.2rem;color:var(--brand)}
.price s{color:var(--muted);font-size:.85rem}
.card .btn{padding:9px 16px;font-size:.92rem;margin-top:8px}
.empty{text-align:center;color:var(--muted)}

.why{background:var(--card);border-block:1px solid var(--line)}
.cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:24px}
.cols span{font-size:1.8rem}
.cols h3{margin:6px 0 4px}
.cols p{color:var(--muted);font-size:.95rem}
.reviews blockquote{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px}
.reviews cite{display:block;margin-top:10px;color:var(--muted);font-size:.88rem;font-style:normal}

details{border-bottom:1px solid var(--line);padding:14px 0}
summary{cursor:pointer;font-weight:600}
details p{color:var(--muted);margin-top:8px}

footer{background:var(--accent);color:#fff;padding:36px 0;margin-top:20px}
.foot{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}
.foot p{opacity:.85;font-size:.92rem;margin-top:6px}
.copy{align-self:flex-end}

.overlay{position:fixed;inset:0;background:rgba(0,0,0,.45);opacity:0;pointer-events:none;transition:.25s;z-index:40}
.overlay.on{opacity:1;pointer-events:auto}
.drawer{position:fixed;top:0;right:0;height:100%;width:min(400px,100%);background:var(--card);z-index:50;transform:translateX(100%);transition:transform .28s;display:flex;flex-direction:column;box-shadow:-8px 0 30px rgba(0,0,0,.15)}
.drawer.on{transform:none}
.drawer-head{display:flex;justify-content:space-between;align-items:center;padding:16px 20px;border-bottom:1px solid var(--line)}
.drawer-head button,.x{background:none;border:0;font-size:1.2rem;cursor:pointer;color:var(--ink)}
.drawer-body{flex:1;overflow:auto;padding:12px 20px}
.drawer-foot{padding:16px 20px;border-top:1px solid var(--line)}
.total{display:flex;justify-content:space-between;margin-bottom:12px;font-size:1.05rem}
.total b{color:var(--brand)}
.line{display:flex;gap:12px;align-items:center;padding:12px 0;border-bottom:1px solid var(--line)}
.line .thumb{width:52px;height:52px;border-radius:8px;flex:none}
.line .t{flex:1;font-size:.92rem}
.line .t small{color:var(--muted);display:block}
.qty{display:flex;align-items:center;gap:6px}
.qty button{width:26px;height:26px;border-radius:50%;border:1px solid var(--line);background:none;color:var(--ink);cursor:pointer}
.rm{background:none;border:0;color:var(--muted);cursor:pointer}

dialog{border:0;border-radius:var(--r);padding:0;width:min(520px,calc(100% - 32px));max-height:92vh;background:var(--card);color:var(--ink);box-shadow:0 20px 60px rgba(0,0,0,.35)}
dialog::backdrop{background:rgba(0,0,0,.5)}
.dlg{padding:24px;position:relative}
.dlg h3{margin-bottom:12px;padding-right:28px}
.x{position:absolute;top:14px;right:16px}
.dlg ul{padding-left:20px;margin:10px 0;color:var(--muted)}
label{display:block;font-size:.88rem;font-weight:600;margin-bottom:12px}
label input,label textarea{display:block;width:100%;margin-top:4px;padding:10px 12px;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--ink);font:inherit}
.muted{color:var(--muted);font-size:.9rem;margin:8px 0}
#qr{display:block;margin:12px auto;border-radius:10px;background:#fff}
.bank{display:grid;grid-template-columns:auto 1fr;gap:6px 14px;margin:12px 0;font-size:.93rem}
.bank dt{color:var(--muted)}
.bank dd{margin:0;font-weight:600;word-break:break-word}
.toast{position:fixed;bottom:24px;left:50%;transform:translate(-50%,80px);background:var(--ink);color:var(--bg);padding:10px 20px;border-radius:999px;transition:.3s;z-index:90;opacity:0}
.toast.on{transform:translate(-50%,0);opacity:1}

@media (max-width:760px){
  .links{display:none}
  .nav-in{justify-content:space-between}
  .hero-in{grid-template-columns:1fr;padding:40px 16px}
  .hero-art{height:230px}
  .book{width:110px;height:165px}
  .sec{padding:40px 16px}
}

.ttl{cursor:pointer}.ttl:hover{color:var(--brand)}
.card .btn.ghost{margin-top:8px}

.auth-link{margin-left:auto;text-decoration:none;font-weight:600;font-size:.92rem;color:var(--ink);padding:8px 14px;border:1px solid var(--line);border-radius:999px;background:var(--card);white-space:nowrap}
.auth-link:hover{border-color:var(--brand);color:var(--brand)}
.links{margin-left:0}
.cp{display:flex;gap:8px;margin-top:4px}
.cp input{flex:1;text-transform:uppercase;margin-top:0}
.cp .btn{padding:8px 18px;margin:0}
.disc{color:var(--ok)}
.ok{color:var(--ok)}.err{color:#c0392b;font-size:.9rem;margin:6px 0}
.dlg h3 small{font-weight:500;color:var(--muted);font-size:.95rem}

/* thuộc tính hidden luôn thắng các luật display khác (vd label{display:block}) */
[hidden]{display:none!important}

.docs{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:12px}
.doc{display:flex;align-items:center;gap:12px;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:12px 14px;text-decoration:none;color:var(--ink);transition:.15s}
.doc:hover{border-color:var(--brand);transform:translateY(-2px);box-shadow:var(--shadow)}
.doc .di{font-size:1.6rem;flex:none}
.doc .dt{flex:1;min-width:0;display:flex;flex-direction:column;gap:2px}
.doc .dt b{font-size:.95rem;line-height:1.3}
.doc .dt small{display:none}
.doc .dg{flex:none;font-size:.8rem;font-weight:700;color:var(--brand);white-space:nowrap}

.logo,.links a{white-space:nowrap}
.links{gap:16px}
@media (max-width:1100px){.links{gap:12px;font-size:.9rem}}

.hero h1{font-size:clamp(1.8rem,4.2vw,2.9rem)}
.book{background-size:cover!important;background-position:center!important}
.stats b{font-size:1.05rem}
/* ảnh bìa khóa học nằm ngang: xếp chồng 3 thẻ */
.hero-art{height:320px}
.book{width:250px;height:156px;border-radius:12px}
.b1{left:0;top:165px;transform:rotate(-5deg)}
.b2{left:14%;top:85px;transform:rotate(2deg);z-index:1}
.b3{left:30%;top:6px;transform:rotate(6deg);z-index:2}
@media (max-width:760px){.hero-art{height:260px}.book{width:190px;height:119px}.b1{top:135px}.b2{top:70px}}

.cart-btn{white-space:nowrap}
@media (max-width:760px){.nav-in{gap:10px}.auth-link{padding:7px 12px}}

.lbl{font-size:.88rem;font-weight:600;margin:4px 0 8px}
.opt{display:flex!important;gap:10px;align-items:flex-start;border:1px solid var(--line);border-radius:10px;padding:10px 12px;margin-bottom:8px;cursor:pointer;font-weight:400}
.opt input{width:auto!important;margin:3px 0 0!important}
.opt small{display:block;color:var(--muted);font-size:.8rem;margin-top:2px}
.opt small.gift{color:var(--ok);font-weight:600}
.opt:has(input:checked){border-color:var(--brand);background:color-mix(in srgb,var(--brand) 6%,transparent)}

label select{display:block;width:100%;margin-top:4px;padding:10px 12px;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--ink);font:inherit}
label select:disabled{opacity:.6}

button.doc{font:inherit;text-align:left;width:100%;cursor:pointer}
#docGate .dlg{max-height:88vh;overflow:auto}